The present invention relates to surface maintenance machines and more particularly to such machines having cylindrically shaped tools which work to remove soilage and debris from the floor surface.
In the past, a variety of floor maintenance machines have been available which sweep and/or scrub a floor surface utilizing a cylindrical brush. As used herein the terms "surface", "floor surface", "maintained surface" and the like will be used to designate or represent those surfaces which require cleaning, such as the floors of buildings (e.g. warehouses), as well as the surfaces of outdoor facilities (e.g. turf, streets, sidewalks and parking lots) and also to designate or represent those surfaces which require scrubbing such as the floors of buildings (e.g. warehouses). Known floor maintenance machines may be either riding units or walk behind units. Sweepers generally include a hopper into which the powered cylindrical brush sweeps dirt and debris. The hopper is constructed in such a manner as to permit dumping of the dirt and debris when desired. Scrubbers generally include a smaller debris hopper into which the powered cylindrical brush or brushes sweep dirt and dirty scrub water. Scrubbers have suitable solution and recovery tanks. Scrubbers also have suitable vacuum squeegee mechanism for removing dirty scrub water from the floor surface and from the debris hopper, depositing such water in the recovery tank. Other surface maintenance machines are available, such as scarifying machines which use cylindrical tools.
Illustrative of power sweepers which utilize cylindrical brushes are the floor maintenance machines described in U.S. Pat. Nos. 3,189,931 (Peabody) and 3,304,572 (Wendel). These sweepers utilize a debris hopper having an attached rubber lip which flexes to admit debris to the sweeping chamber and drops back into place to block the passage therebeneath of debris swept forwardly by the brush. Scrubbing machines which utilize a cylindrical brush are illustrated in U.S. Pat. Nos. 3,197,798 (Brown et al.) and 3,702,488 (Kasper). The Tennant.sup.R Model 265 Power Sweeper (trademark of Tennant Company) and U.S. Pat. No. 3,197,798 are illustrative of units which are convertible from a sweeper which utilizes a cylindrical brush to a scrubbing machine which also utilizes a cylindrical brush. U.S. Pat. No. 3,702,488 shows a scrubbing machine which uses two driven brushes to work a scrubbing solution on the floor. The cylindrical brush or brushes of a scrubbing machine serve to work a scrubbing solution on a maintained surface to loosen soilage. The cylindrical scrubbing brush may also lift spent scrubbing solution, dirt and debris into a suitable tray or tank.
In the present invention, it was found advantageous on a floor maintenance machine, for example, a sweeper, to include a powered rotary lip for use in conjunction with the cylindrical brush. In a sweeper, the rotary lip serves to function performed by conventional lips and seals the forward side of the brush housing to assist in maintenance of the vacuum in the housing. The rotary lip permits movement of large debris such as cans and bottles therebeneath. This permits use of a more elevated hopper bottom, thus providing improved clearance and eliminating the need for a conventional rocking hopper (see U.S. Pat. No. 2,701,377) thereby simplifying the structure. By allowing more clearance under the hopper bottom, the rotary lip permits movement of large debris such as cans, bottles, rocks, and scrap lumber therebeneath, and tends to reduce or prevent pushing of such debris which is more of a problem with sweepers having a stationary flexible lip. The rotary lip also provides a more elevated projection of the debris. Because the rotary lip is powered, it also positively pulls debris into the sweeping chamber and feeds it to the sweeping brush. This makes it possible, on a machine with the hopper behind the main sweeping brush and with a relatively large rotary lip, to drive up to a pile or heavy accumulation of bulky debris and pull it into the machine and load it. Such an operation is highly desirable in many types of clean-up operations. The elevated projection also permits use of an inlet wall for the hopper e.g. four sided hopper, resulting in an increased useful volume for the hopper. The rotary lip assures a more complete filling of the sweeper hopper particularly when lightweight debris is being picked up. In other words, the rotary lip assists in projecting the lightweight debris well into the hopper. The rotary lip may serve as an impeller and create desirable air currents which act to move lightweight debris well into the hopper.
Use of the present powered rotary lip in a scrubber is advantageous since improved debris pickup is obtained and a significant portion of the dirty scrub water is also lifted thus reducing the load on the squeegee.
The present invention provides greater efficiency on lifting debris from the maintained surface. A problem encountered with conventional sweeping equipment is that lightweight debris such as paper and aluminum cans may accumulate immediately in front of the stationary flexible lip seal. This is especially a problem during operation on smooth floor surfaces. The present rotary lip overcomes this problem and draws such debris into the pick-up zone where the debris is thrown by the lip into contact with the brush at an elevated point on the brush, thereby facilitating movement of the debris into the hopper. The present invention also minimizes the effect of a common difficulty encountered in the past wherein debris has been projected forwardly beneath the front lip or skirt of the sweeping brush housing. The present rotary lip serves as a more effective seal than previous seals in retaining debris within the brush chamber. Known sweepers tend to lose sweeping efficiency as the brush becomes worn, whereas the present invention maintains a greater degree of efficiency throughout the brush wear life.
It has been known in the past to use a nonpowered rotatable lip seal to permit larger debris to reach the brush, for example, see U.S. Pat. Nos. 3,584,325 (Larson et al) and 3,513,498 (Bennich). The Larson et al patent has a flap-type lip seal which is rotated only when larger pieces of debris are encountered thereby permitting the larger debris to pass beneath the seal. In this case the rotatable lip does not assist to any significant extent in the projection of debris into the hopper. The Bennich patent shows a lip comprised of a tubular deflector mounted on an elongated rod. The tubular deflector is loosely mounted on the rod. In this case again the deflector does not assist to any significant extent in the projection of debris into a hopper. Rather the deflector prevents or minimizes projection of debris forwardly.
It has also been known in the past to use a pair of power-driven brushes, for example see U.S. Pat. No. 2,054,713 (Randolph). In this patent a larger powerdriven brush is used in conjunction with a smaller powerdriven brush. The smaller brush is held in locked position in contact with the surface being swept and is prevented from moving vertically with respect to the larger brush, thereby preventing the entry of large debris items under the smaller brush. Various other counter-rotating dual brush sweepers have been known.